Matrix metalloproteinase-9 (MMP-9) and tissue inhibitors of metalloproteinases 1 (TIMP-1) play important roles in the function of the blood–brain barrier. Serum MMP-9 and TIMP-1 concentrations were determined in influenza virus infection with or without neurologic complications. Our results suggest that an imbalance between MMP-9 and TIMP-1 damages the blood–brain barrier and promotes febrile seizure or encephalopathy in influenza virus infection.
From the *Department of Pediatrics, Yamaguchi University School of Medicine, Yamaguchi, Japan; and the †Department of Pediatrics, Okayama University Graduate School of Medicine and Dentistry, Okayama, Japan.
Accepted for publication January 19, 2007.
This study was supported by grants from the Ministry of Health, Labor and Welfare (H18-Shinkou-6) and the Ministry of Education, Culture, Sports, Science and Technology (A-17209037).
Address for correspondence: Takashi Ichiyama, MD, Department of Pediatrics, Yamaguchi University School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan. E-mail: firstname.lastname@example.org.